In radio cellular networks, a base station defines a radio coverage cell.
Herein after, we use the terminology which is common in radio cellular network like CDMA (Code Division Multiple Access), GSM (Global System for Mobile communication) or UMTS (Universal Mobile Telecommunication System) networks.
There exists base station connected to a plurality of distributed remote radio antennas, each of the remote antennas defining a respective radio coverage zone in the cell. Such a base station is useful to ensure indoor cellular radio coverage in a building or in several buildings. To this end, for example, the remote antennas are placed on different floors of the building. Typically, these remote antennas are connected to tire same transceiver through a local network so that die mobile station receives the same signal from multiple and physically separated radio antennas. These multiple copies of the same signal are treated by the mobile station as though they were radio reflections.
It may be necessary to locate a mobile station within a particular zone of such a cell. To this end, the mobile station location can be determined using time offsets measured on data uplink transmission. It is reminded that uplink transmissions are data transmissions from the mobile station to the base station. On the contrary, downlink transmissions are data transmissions from the base station to the mobile station.
Such a location method is not easy to implement and does work only if the number of distributed remote antennas remains small, i.e. inferior to ten.
An example of a radio cellular network with distributed radio antennas is described in US 2005/0157675 to Feder et al.